Civil Engineering Design functions

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bernd
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Re: Civil Engineering Design functions

Postby bernd » Tue Nov 10, 2015 2:09 pm

aeroSurveyor wrote:just tried again. Have m/kg/s and 3 decimals set on v. 0.16 from 04.11.2015. First, is the decimal a comma or a point on a german (win7 64bit) operating system?
The very bottom right is definitely wrong (30.76 x 16.47m), this is a large area of a digital terrain model, approx. 30000 x 16000 m could be right.

Now on the 0.16 version, I get three digits after the comma, so either I don't get any decimals at all or the figure is wrong by 1000 (if the decimal separator is supposed to be point).
on my german freecad komma is the decimal. If you would post a small point cloud we may find the culprit faster.
Mar10n
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Re: Civil Engineering Design functions

Postby Mar10n » Tue Nov 10, 2015 10:54 pm

Hi. I`m working as an engineer on water sewer and road constructions. It´s good to see that you guys are looking inn to an area of design that has huge need for someone too rattle the cage :)

I have read the posts here and it´s seems like you have a basic understanding of the task. So I will just name some basic things that i´d think you need to focus on in the process.

The main focus for us doing civil engineering is the reference line and the terrain. Like architects work with construction lines we work with reference lines. So you will have to find a way to implant this in freecad if you want to be able to build water and sewer pipes and roads.

We basically build everything around this line by referring to it. Like if I have a center line (reference line 0) of a road I will say that the next line is 2meters to the right from this and 3% lower (decline). This line would in my world be called 0.1 and a line to the left would bee -0.1 or -1.1 if it´s the roads shoulder. Then by telling how far along the reference line it should be 2m to the right, I have made a area, and by defining offset Z of this area I have made a volume and so on.

The reference line also is the one giving us the long section and guiding the cross section. You can´t use the section cut from standard CAD section cut on long section since the road turns in curves, not straight corners. It also has to be able to show pipes that is on both sides of the long section cut line.
The cross section is used to calculate volumes by slicing the road up and finding the volumes between these cross sections.

The terrain has to be triangulated in order too be precise enough and to be able too correlate with the road model. There is some serious calculus in this, but it seems like you guys have already the basic tools to make it work.

In addition to this you will (unless you find a better solution) have to implant break lines. Lines that defines were the built of the road should stop. Like if you have a road coming on to another road you have to make a break line to define what the volume and area of each of those roads are.

As to format I think you should focus on GML, LandXML, (cityXML) and maybe IFC. There is a jungle of formats out there, but thees are the ones that have the best outlook for becoming the new standard, and they are open.
aeroSurveyor
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Re: Civil Engineering Design functions

Postby aeroSurveyor » Tue Nov 10, 2015 11:25 pm

If the comma is the decimal separator, then what I marked green is correct and red is wrong in the attached image. Hope it's easier to see here. The distance should be 10555,2 m and not 10,5552 m. The coordinates of P1 and P2 are read correctly. This is v. 0.16 and units set to m/kg/... and 2 decimals.
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yorik
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Re: Civil Engineering Design functions

Postby yorik » Thu Nov 12, 2015 6:37 pm

very useful input Mar10n thanks!

indeed this baseline seems the very fundamental tool. Basically a 3D multi-segments curve (a wire in OCC terms). The good thing isthat all the geometrical operations (offset, etc) are already there. One would need to add a series of metadata to it I think (ranges, markers, etc)
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yorik
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Re: Civil Engineering Design functions

Postby yorik » Fri Nov 13, 2015 5:41 pm

I've been playing a bit with GRASS... The python interface is a bit unusual, but there are lots of possibilities there!
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sanzo
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Re: Civil Engineering Design functions

Postby sanzo » Sun Nov 15, 2015 4:55 pm

wow, this discussion is growing with very useful information and ideas!
I agree with yorik that if there's a software that does a good job at what it does, trying to implement the same functions is only wasted time (a la UNIX style).
The problem with this philosophy is that most of the time the interoperability is not so good (even with SW of the same vendor, just as my recent experiences with the famous proprietary CAD and BIM software), and developers should try to ease things in this perspective.

I tried to import an IFC file of a small tunnel exported from Revit, and ifcOpenShell imported most (but not all) of the solids (they were ifcProxyObject, ie generic solids).
I saw that no parameters/properties are kept (or maybe I couldn't find them in FreeCAD). One of the best thing of IFC files (from my point of view) is that you can assign many properties to an object, even if it's not a standard ifc property, and it will be read by other IFC viewers. We use it to pass information from revit to BOM software (ie the amount of steel needed by a particular tunnel cross section without the need of drawing them, or the actual length of a section when we model only a typical 1m long section)
Having the option to view, and also edit or add properties in the IFC file (and thus in FreeCAD model) would be wonderful!

I discovered that buildingSMART alliance accepted the IFC extension IfcAlignment based on LandXML. It will take many months for it to become a standard used in major vendors softwares, but I hope something will show up soon. They're also working on ifcRoad, ifcBridge and IfcTunnel, using IfcAlignment as the base.

I think one of the best way to start is to build a LandXML importer (and exporter?) and map all the possible LandXML objects to FreeCAD objects! For now I only found a QGIS importer but it works only on cadastral survey data.
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bernd
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Re: Civil Engineering Design functions

Postby bernd » Sun Nov 15, 2015 5:12 pm

sanzo wrote: I tried to import an IFC file of a small tunnel exported from Revit, and ifcOpenShell imported most (but not all) of the solids (they were ifcProxyObject, ie generic solids).
I saw that no parameters/properties are kept (or maybe I couldn't find them in FreeCAD). .
There is development on ifc in FreeCAD going on all the time. Some times more some times less but going on. Would you provide the ifc file or a minimal ifc which shows the problem you had. Best would be to open a new thread in this regard (import ifc properties) in the Arch section of the forum.
M-Rick
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Re: Civil Engineering Design functions

Postby M-Rick » Thu Nov 19, 2015 5:43 pm

yorik wrote:I've been playing a bit with GRASS... The python interface is a bit unusual, but there are lots of possibilities there!
And GRASS is totally part of QGIS now.

There is also a good set of urban civil engineering python tools with Urban Data Science Toolkit and UrbanSim.

http://www.udst.org
https://github.com/UDST/urbansim

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Asphalt
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New geometry objects and functions needed

Postby Asphalt » Sun Jan 24, 2016 7:44 am

Very good initiative and it would be great to make road design in Freecad while today there is really not a free, as far as I have been able to find out, an open solution for this in particular.

In addition to the import of maps, survey and coordinate data handlling there is 1 essensial thing that need to be made that is not in Freecad today: The horisontal and vertical road geometry design functions. The most important is to establish the horisontal alignment function. To do this there is a need to introduce the clothoide or spiral geometry element. This is a geometry element that are used in road design to make the driver feel more comfortable when transfer from a stright roadline and into a curbe. Thats why this geometric element e.g. between a line to a curbe as well are called a transtition curbe while it gradually decrease from radius 0 to the actual curbe radius over the lenght of the clothoide element.

After the clothoide are defined as a geometry (2D) object in Freecad the next task will be to make a good horisontal alignment design function (that integrates the 3 basic horisontal elements stright line, clothoide and curbes together). This to make engineers able to in a easy and elegant way design road geometry inside the editor.

Then after that there will be needed to make a vertical design function but the geometric chalenges are simpler than for the horisontal.

Then a longitudinal profil (terrain longitudinal cut along the horisontal line) function must be made and the vertical alignment function will be used in this projection to make the final vertical design with the function mentioned above.

I have some ideas how to make the above more in details but i am not a programmer but if someoene are interested in start I can help provide more data as formulas and suggestion for a user interface etc.

There is a lot of other things to be done to but if we could start with this it will bring us a far step further and give at least some useable functions that im sure will be appreciated and taken in use by a new and hungry group of users that have been left out from the open source Freecad world far to long.
jmaustpc
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Re: New geometry objects and functions needed

Postby jmaustpc » Sun Jan 24, 2016 8:05 am

Asphalt wrote:Very good initiative and it would be great to make road design in Freecad while today there is really not a free, as far as I have been able to find out, an open solution for this in particular.
Your first post, welcome to FreeCAD